LTC3780EG Datasheet, PDF (4/30 Pages) Linear Technology – High Efficiency, Synchronous,4-Switch Buck-Boost Controller

LTC3780
Electrical Characteristics The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T_A = 25°C. (Note 7) V_IN = 15V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN TYP MAX UNITS
DF MAX, Boost Maximum Duty Factor
% Switch C On
99
%
DF MAX, Buck Maximum Duty Factor
% Switch A On (in Dropout)
99
%
V_RUN(ON)
I_SS
V_SENSE(MAX)
RUN Pin On Threshold
Soft-Start Charge Current
Maximum Current Sense Threshold
V_{SENSE(MIN,BUCK)}
TG1, TG2 t_r
TG1, TG2 t_f
BG1, BG2 t_r
BG1, BG2 t_f
TG1/BG1 t_1D
Minimum Current Sense Threshold
TG Rise Time
TG Fall Time
BG Rise Time
BG Fall Time
TG1 Off to BG1 On Delay,
Switch C On Delay
V_RUN Rising
V_RUN = 2V
Boost: V_OSENSE = V_REF – 50mV
Buck: V_OSENSE = V_REF – 50mV
Discontinuous Mode
C_LOAD = 3300pF (Note 5)
C_LOAD = 3300pF (Note 5)
C_LOAD = 3300pF (Note 5)
C_LOAD = 3300pF (Note 5)
C_LOAD = 3300pF Each Driver
1
1.5
2
V
0.5
1.2
µA
l 120
160 185
mV
l –95 –110 –150
mV
–6
mV
50
ns
45
ns
45
ns
55
ns
80
ns
BG1/TG1 t_2D
BG1 Off to TG1 On Delay,
Synchronous Switch D On Delay
C_LOAD = 3300pF Each Driver
80
ns
TG2/BG2 t_3D
TG2 Off to BG2 On Delay,
Synchronous Switch B On Delay
C_LOAD = 3300pF Each Driver
80
ns
BG2/TG2 t_4D
BG2 Off to TG2 On Delay,
Switch A On Delay
C_LOAD = 3300pF Each Driver
80
ns
Mode
Transition 1
BG1 Off to BG2 On Delay,
Switch A On Delay
C_LOAD = 3300pF Each Driver
250
ns
Mode
Transition 2
BG2 Off to BG1 On Delay,
Synchronous Switch D On Delay
C_LOAD = 3300pF Each Driver
250
ns
t_{ON(MIN,BOOST)}
Minimum On-Time for Main Switch in Switch C (Note 6)
Boost Operation
200
ns
t_ON(MIN,BUCK)
Minimum On-Time for Synchronous
Switch in Buck Operation
Switch B (Note 6)
180
ns
Internal V_CC Regulator
V_INTVCC
Internal V_CC Voltage
∆V_LDO(LOADREG) Internal V_CC Load Regulation
V_EXTVCC
EXTV_CC Switchover Voltage
∆V_EXTVCC(HYS) EXTV_CC Switchover Hysteresis
∆V_EXTVCC
EXTV_CC Switch Drop Voltage
Oscillator and Phase-Locked Loop
7V < V_IN < 30V, V_EXTVCC = 5V
I_CC = 0mA to 20mA, V_EXTVCC = 5V
I_CC = 20mA, V_EXTVCC Rising
I_CC = 20mA, V_EXTVCC = 6V
l 5.7
6
6.3
V
0.2
2
%
l 5.4
5.7
V
300
mV
150 300
mV
f_NOM
f_LOW
f_HIGH
R_PLLIN
I_PLLLPF
Nominal Frequency
Lowest Frequency
Highest Frequency
PLLIN Input Resistance
Phase Detector Output Current
V_PLLFLTR = 1.2V
V_PLLFLTR = 0V
V_PLLFLTR = 2.4V
f_PLLIN < f_OSC
f_PLLIN > f_OSC (Note 9)
260 300 330
kHz
170 200 220
kHz
340 400 440
kHz
50
kΩ
–15
µA
15
µA
3780ff
4
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